I read “Before Antietam: the Battle of South Mountain,” by John Michael Priest, almost 3 years ago. “Unholy Sabbath” is another book-length treatment of the Battle of South Mountain, which is often overshadowed by the bloodier Battle of Antietam, which occurred 3 days later and only a few miles away.
The two books are fine complements to each other. Priest tends to focus extensively on tactical details. While Brian Matthew Jordan, this book’s author, does delve into the tactics, he also examines the battle in the larger context of Lee’s Maryland Campaign. Jordan convincingly argues that South Mountain was the turning point of the campaign, in that it altered Lee’s strategy from proceeding into Pennsylvania, as he would do 9 months later. Instead, immediately after the defeat at South Mountain, Lee determined to regroup at Sharpsburg, with the intent to retreat across the Potomac.
The author has excellent discussions of the fighting at the three gaps (Crampton’s, Fox’s, and Turner’s). He assesses the successes and failures of the various commanders. The maps by Bradley Gottfried, are to the regimental and, at times, company level, and serve to illustrate the varied terrain of the battlefield.
In a concluding chapter, the author discusses the larger impact of South Mountain and how it was remembered in both Union and Confederate literature. I highly recommend this book for a detailed account of the Battle of South Mountain.